The Waterfall Illusion (also known as the Motion Aftereffect) a visual illusion experienced after viewing a moving visual stimulus, and then fixating a stationary stimulus. The stationary stimulus appears to move in the opposite direction to the original stimulus.
For example, with a waterfall, after fixating on the falling water for several seconds, when one shifts their gaze to the surrounding rocks, they will appear to move up briefly in the opposite direction of the waterfall
If you focus on the falling water for several seconds, then shift your gaze to a still object, that object will appear to shift upward in the opposite direction of the waterfall
Table of Contents
- How does the Waterfall Illusion work?
- Versions of the Waterfall Illusion
- Illusions like the Waterfall Illusion
- Discovery of the Waterfall Illusion
- References and Resources
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How does the Waterfall Illusion work?
The waterfall illusion is a visual illusion that occurs when a person looks at a waterfall or a rapidly flowing stream.
This illusion is created by the persistence of vision, which occurs when the image of the moving water is retained in the retina for a short period of time after the stimulus is removed.
The brain interprets this as if the water is still moving, and it results in the stationary image to appear to move.
The illusion can also be observed in other types of flowing fluids such as lava, and in moving visual patterns like scrolling text or a zig-zag pattern.
Versions of the Waterfall Illusion
The following are some other examples of the Waterfall Illusion
Illusions like the Waterfall Illusion
The following are some illusions that are related to Waterfall Illusion
Motion-induced blindness (MIB) is an optical illusion that occurs when a stationary pattern or image is presented in the presence of a moving pattern or image. The stationary pattern or image appears to disappear or fade, even though it is still present, this phenomenon is called motion-induced blindness.
Troxler’s fading, also known as Troxler’s effect, is a phenomenon in which a stationary visual stimulus eventually disappears from perception, even though it is still present in the visual field.
This occurs because the human visual system adapts to constant stimuli and eventually stops responding to them.
After staring at the cross for several seconds, the dots fade away
After staring at the cross for several seconds, colors fade away
After staring at the dot for several seconds, the colored ring fades away
The Phi phenomenon is the illusion of movement created by the rapid succession of static images or light sources.
It is the perceptual phenomenon that explains how the human brain perceives motion when presented with a sequence of still images or light sources that are displayed in rapid succession.
The Rotating Snakes is a peripheral drift illusion that consists of a grid of shapes, with some of them appearing to be rotating or undulating. The illusion is created by the interaction of the shapes with the neural processing of the visual system.
The Moiré pattern illusion: This illusion is created by superimposing two similar patterns on top of each other, such as a grid of lines or circles. The resulting pattern appears to be moving or changing.
The Scintillating Grid Illusion, in which a grid of black and white squares appears to pulsate or “breathe” when viewed from the periphery of the image.
The Hermann Grid Illusion, in which the intersections of a white grid on a black background appear to be gray, even though they are actually the same color as the background.
The Zöllner Illusion, in which parallel lines appear to be tilted or bent when intersected by diagonal lines.
The Café Wall Illusion is a visual illusion that is created by a grid of alternating light and dark horizontal and vertical lines. The lines appear to be bent or tilted, even though they are actually straight.
Discovery of the Waterfall Illusion
Some believe that the Waterfall effect (or the Motion Aftereffect effect) was first observed and noted by Aristotle in approximately 350 BC.
More recently, the effect was described by German physicist and physician Johann Christoph Friedrich von Schiller in 1812.
He observed that after looking at a rotating wheel for a period of time, stationary objects appeared to rotate in the opposite direction. He called this phenomenon the “spinning wheel illusion.”
However, the phenomenon was independently discovered by several other researchers in the 19th century including Peter Mark Roget and Charles Wheatstone.
References and Resources
Check out our complete list of illusions.
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